Does 2Do support the Synology CalDAV server?
Sadly, not the one we’ve tested against. Although 2Do v2+ on the Mac and v3+ on iOS work with most, if not all, 3rd party CalDAV servers, we have been unsuccessful in getting it to work with the one Synology server we tried so far. Their online help documentation is sparse, and there’s a lot of confusion about how it’s configured by default (ports, user principal location etc). If you yours working with 2Do, please share your configuration with us!